CUDA ERROR: Launch failed in cuCtxSynchronize()” and “cuCtxCreate: Launch failed” when Rendering in Cycles using GPU
Bumped into the same error once.

Found following thread at developers forum:


  Then it occurred to me that the Gforce Experience runs in the background (and being in my opinion, not a well written program) may be overlapping the memory of Blender or at least hogging the memory. So I un-installed it and magic! All Cuda errors and memory errors went away. Blender works again as it should!